1. Field of the Invention
This invention relates to a die attach material curing apparatus and method and, more specifically, to a radiant energy die attach material curing apparatus and method.
2. Brief Description of the Prior Art
In the fabrication of semiconductor devices, the cure process for die attach materials is generally achieved via a batch process in a large nitrogen purged convection oven. Die attach involves curing of the die attach material, generally an epoxy, which secures the semiconductor die to the leadframe. Other solutions to the stand alone "snap cure" of die attach material use heater block contact and/or forced convection technology to transfer energy to the target.
In the batch process, the leadframes and semiconductor die (or dies if plural leadframes are used) are secured together with a die on each leadframe by placing the die over the uncured die attach paste material and then placing the leadframe strips in carriers. These carriers are fed into a chamber, which is a forced air and convection oven, for a predetermined period of time, usually several hours, the temperature in the chamber being determined by the type of die attach used and other well known factors. The heat in the chamber heats up the die and the die attach material and causes crosslinking of the die attach polymer adhesive material with the die thereby being secured to the die attach material and to the leadframe.
The prior art die attach material cure processes as described above require a relatively long curing time and also are relatively dirty due to the outgassing caused as a result of the curing process. The materials resulting from the outgassing remain at least in part in the chamber and can deposit on the semiconductor die, thereby causing a possible degrading of the electrical properties of the final semiconductor device. It is therefore apparent that better die attach material curing techniques are highly desirable.